On Thu, 9 Feb 2023 at 14:08, Singh, Mithun via Gcc-help <gcc-help@xxxxxxxxxxx> wrote: > > Hello, > > I have typedef void as follows in one of my header files: > > typedef void VOID; > > And I am using this typedef as function parameter as follows: > > VOID someFunction(VOID); Why would you want to do that? It's just silly. > This code compiles fine with gcc 3.3.5, but when I compile it with gcc 4.4.2, I get following error: Why are you using such ancient versions? It's not 2009. > > error: '<anonymous>' has incomplete type > error: invalid use of 'VOID' > > Will you please shed some light on why would it not work with gcc 4.4.2? Because the C++ standard says it's not valid, and GCC got fixed to follow the standard. A function with no parameters can only be declared with () or (void), not with a typedef to void. The tokens "(void)" have special meaning for compatibility with C, but (VOID) is nonsense. See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=9278
